1. Field of the Invention
The invention relates to a play-free and centering tube of a textile machine. Couplings of this type consist of at least three driving elements which are arranged in a tube receptacle connected nonpositively to the spindle shank, the tube coupling being supported centrically type are required in the textile industry, preferably in spinning and twisting mills.
2. Discussion of Background Information
Tube couplings of the generic type have already been developed. Thus, DE 41 31 498 A1 describes the tube coupling for a spinning or twisting spindle, in which movable driving bodies are used, which are pressed against the inner face of the tube as a result of the centrifugal force. They make a nonpositive and/or positive-connection there between the spindle upper part and the tube and thus make it possible to transmit a torque. On account of the low masses of the movable parts, the available centrifugal forces are relatively low, and therefore a reliable drive of the tubes on the spindle upper parts cannot be ensured. Moreover, at low rotational speeds of the spindles, the coupling has an insignificant effect, so that, particularly when the spindle is being braked, the tube slips on the spindle upper part. This has an adverse affect both on the yarn quality and on the wear of the tube.
Furthermore, DE 42 17 381 A1 describes a tube coupling which is likewise designed as a centrifugal coupling. This centrifugal coupling is located in an extension of the drive wharve, and, because of the relatively low driving forces, a sleeve having a profiled inner face is provided. In this solution, the driving action is reinforced in that there is only a very slight dimensional play between the outside diameter of the tube coupling and the inside diameter of the tube.
DE 43 18 027 A1 discloses a tube coupling intended for making a nonpositive connection between the tube and the spindle upper part by means of variously designed driving bodies. Due to the centrifugal forces which arise, the driving bodies are set in wobbling motion, with the result that they are clamped between the spindle upper part; and the tube. The disadvantage of this type of tube coupling is that the tube is not reliably driven centrically to the spindle axis. Another disadvantage is that this nonpositive clamping connection does not come loose easily when the spindle is at a standstill. Furthermore, it may happen that the driving bodies themselves do not assume a centric position to the spindle axis, this being conducive to the development of unbalances. Moreover, the stability of the spindle upper part is weakened due to the receiving bores for the driving bodies.
Finally, DE 195 37 762 A1 describes a technical solution which is to be suitable particularly for spinning tubes with lower yam masses. In this case, considerable acceleration for starting up the spindle is necessary in order to rotate the rotatable ring in the ball guide. This solution is not suitable for bridging pronounced dimensional differences between the tube inside diameter and the outside diameter of the tube coupling. Since the driving bodies fall down as a result of their inherent mass when the spindle is at a standstill, cantering of the tube can no longer be ensured.
The known technical solutions have in common the defect that they do not offer a sufficient safeguard for reliable centering of the bobbin tube relative to the spindle axis and for the simple removal of the wound tubes from the spindle upper parts. As is known, draw-twist tubes are deformed as a result of the winding forces in such a way that, if there is insufficient play between the inside diameter of the tube and the outside diameter of the tube coupling, the firm fit regularly presents problems when the tube is drawn off.
The object of the invention, therefore, is to overcome the defects of the known prior art and to provide a tube coupling for spinning or twisting spindles which ensures unimpeded functioning even when there are pronounced dimensional differences between the inside diameter of the tube used and the outside diameter of the tube coupling.
Moreover, the technical solution is to ensure that a possible deformation of the tube when the latter is being wound with thread material is riot detrimental to the centric position of the tube to the spindle axis and the reliable drive of the tube by the spindle. It is to become possible, furthermore, to ensure that tube deformation, which is usually to be seen when plastics are used as tube material and because of high thread forces, does not lead to the firm fit of the tube on the spindle when the latter is at a standstill, so that the draw-off of the tube by hand or by means of tube draw-off devices can easily be ensured. The technical solution to be provided will also be distinguished by a simple design and easy assembly.
According to the invention, a play-free and centering tube coupling for the spindle of a textile machine, includes of at least three driving elements which are arranged centrically so as to bear against an inner wall of the tube, in a tube receptacle connected nonpositively to the spindle shank. A basic body of a thrust piece is axially moveably arranged in the tube receptacle and an end piece fixedly connected to the basic body. The driving elements are arranged so as to be movable predominantly radially between the basis basic body and the thrust piece, and guide slopes, which are in contact with the driving elements and are in the form of a conically designed collar are arranged on the thrust piece. Detaining centrifugal elements, which are displaceable predominantly radially, are arranged between the thrust piece and the end piece, and at least one of the faces of the thrust piece and of the end piece, which are in contact with the detaining centrifugal elements, is designed as a guide slope.
According to the aforementioned invention a play-free and centering tube coupling for the spindle of a textile machine includes at least three driving elements which are arranged centrically in a tube receptacle and come to bear nonpositively on the inner wall of the tube. For this purpose, the tube receptacle includes a basic body, of a thrust piece arranged axially movably therein and of an end piece fixedly connected to the basic body. The driving elements are arranged between the basic body and the thrust piece and are designed to be movable predominantly radially. Arranged on the thrust piece is a conically designed collar, of which the parts which are in contact with the driving elements function as guide slopes. Moreover, detaining centrifugal elements displaceable predominantly radially are arranged between the thrust piece and the end piece. Finally, the fundamental design of the tube coupling includes the fact that at least one of the faces of the thrust piece and of the end piece which are in contact with the detaining centrifugal elements is designed as a guide slope. The entire tube coupling therefore consists solely of simple components which can be produced and assembled efficiently. In particular, it fulfills the aim of ensuring that, if required, even those bobbin tubes can be received which are subject to deformations as a result of high thread forces and, if tube couplings known hitherto are used, may cause complications in the necessary removal from the spindle upper part.
By contrast, with the newly developed tube coupling, any desired geometric plays between the outer circumference of the tube coupling and the inside diameter of the nonloaded tube can be selected, so that not only can the manufacture of the tube coupling be carried out in a virtually completely mechanized and automated manner, but the requisite fault-free mechanized or manual attachment and removal of the tubes on the respective textile machine can also take place.
Furthermore, the particular advantage of the proposed tube coupling is that, even when the respective spindle is at a standstill, the tube is centered relative to the spindle axis and, consequently, unbalances, with the resulting consequences for the respective spindle and for the winding of the tube, can be ruled out. This purpose is served by the driving elements, which are uniformly displaced predominantly radially by the axially movable thrust piece via the guide slopes arranged on the latter and, by partially emerging from the receptacles formed on the basic body of the tube coupling, brace the coupling-covering tube against the basic body. When the spindle is in the working state, at the normal rotational speeds, it is not only the driving elements which are pressed outward against the tube inner wall as a result of centrifugal forces which arise, but also the detaining centrifugal elements which are arranged between the thrust piece and the end piece. These reinforce the normal forces which act in any case in the movable thrust piece, with the result that the radial forces on the driving elements are reinforced even further. When the winding of the tube is concluded and the spindle is at a standstill, these reinforcing forces lapse, so that the respective tube can be easily detached from the tube coupling, with only the forces having to be overcome which act on the driving elements as a result of the inherent mass of the thrust piece via the guide slopes arranged on the latter.
There is provision for the difference in dimensions between the outer radius of the basic body and the outer radius of the middle cylindrical part of the thrust piece to have at least the size of the diameter of the spherical driving element.
Alternatively to this, the difference in dimensions between the outer radius of the basic body and the outer radius of the middle cylindrical part of the thrust piece amounts at least to the overall dimension of the spherical part of the driving element, together with the attached cap-shaped part of the driving element.
This ensures that, if required, the driving elements may be arranged completely within the outside diameter of the basic body of the tube coupling, this being conducive to the easy attachment of the tube onto the tube coupling and to removal from the latter.
In a particular embodiment of the invention, therefore, the driving elements are designed as balls or as caps in conjunction with inner balls. In the last-mentioned design variant, there is consequently the possibility of having the capability of making area contacts between the tube coupling and the inner wall of the tube and therefore, if appropriate, of transmitting relatively high driving forces to the tube, whilst at the same time avoiding local deformations of the latter.
Preferably, the cap-shaped part of the driving element is equipped with a stop collar, with the aid of which the cap is prevented from emerging completely from the basic body of the tube coupling. The receptacles for the driving elements are arranged radially in the basic body and may be designed, if balls are used as driving elements, as a cylindrical bore or, if driving elements are used as a combination of cap-shaped parts and of balls partially surrounded by the caps, as a perforation of virtually any desired cross section, for example a prismatic cross section.
In order to prevent the balls, as sole driving elements, from emerging, the cylindrical bores are designed with an outer spherical narrowing in the basic body.
While, in every embodiment of the invention, a guide slope is arranged on the thrust piece for the purpose of the radial emergence of the driving elements from the basic body, the arrangement of guide slopes for the detaining centrifugal elements located between the thrust piece and the end piece may be restricted, as required, to one guide slope. In this case, the rolling tracks for the detaining centrifugal elements designed as cylindrical rollers or balls have inclinations relative to the horizontal, either on the end piece fixedly anchored to the basic body or on the thrust piece. The fundamental difference between the guide slope for the driving elements and the guide slopes for the detaining centrifugal elements is that the guide slope arranged on the thrust piece for displacing the driving elements is designed such that it widens outward.
By contrast, the guide slopes of the guide tracks for the detaining centrifugal elements are designed so as to widen inward. However, all the guide slopes may have selectable inclinations relative to the horizontal. This makes it possible, in design terms, to satisfy the various requirements arising from the actual rotational speed, the actual thread tension and the type of material of the bobbin tube. The selection of the inclinations of the guide slopes, on the one hand, determines the force action by which the driving elements are pressed against the inner wall of the bobbin tube when the thrust piece is under axial load. On the other hand, the selection of the inclinations of the guide slopes in the tracks for the detaining centrifugal elements determines the force which, under the action of centrifugal force, applies the detaining centrifugal elements to the thrust piece in the axial direction. In a particular embodiment, the selectable angle of the guide slope for the driving elements on the thrust piece is preferably 40xc2x0 relative to the horizontal.
By contrast, the guide slopes arranged in the guide tracks for the detaining centrifugal elements have a selectable angle, preferably 10xc2x0 relative to the horizontal. For the uniform guidance of the thrust piece during axial downward displacement by means of the detaining centrifugal elements, it is sufficient if at least three radially arranged guide tracks are formed between the end piece and the thrust piece.
However, in order to increase the action of force on the axially displaceable thrust piece as a result of generally higher overall masses of the detaining centrifugal elements, the number of guide tracks may also be increased.
A further embodiment of the invention provides for the thrust piece to be equipped with a sliding bush ensuring the easy axial displaceability of the thrust piece on the spindle shank.
On account of the relative inaccessibility of the installed tube couplings and, in particular, of this sliding-bush, a plastic bush, for example made of PTFE, is preferably selected for producing the sliding bush.
Overall, the tube coupling is designed in such a way that it contains predominantly individual elements which can be produced in automatic manufacturing steps. In addition, the proposed solution is also distinguished in that the assembly of the developed tube coupling can likewise be carried out in a predominantly automated manner.
For this purpose, for fixing the end piece, the basic body has arranged on it an assembly collar for the fit of the end piece in the basic body.
There is provision, moreover, for producing between the basic body and the end piece a positive connection to be made after the conclusion of the assembly of the tube coupling, for example by means of a deforming pressing operation.
It may be advantageous to arrange between the end piece and the thrust piece a compression spring which ensures the lowest possible position of the thrust piece in each case in the basic body. What is achieved thereby is that, in addition to the inherent mass of the thrust piece, a further force component presses the driving elements against the inner wall of the spindle tube, even with the spindle at a standstill, and consequently ensures that the spindle tube is centered on the spindle shank. This may be important for starting up the spindle, while at the same time avoiding unbalances. Moreover, the defined driving force assists the use of equipping and removing mechanisms on the respective textile machine.
A further particular embodiment of the tube coupling is characterized in that an elastic band is arranged on the outer circumference of the basic body in the plane of passage of the driving elements through said basic body. This band covers the receptacles for the driving elements and leads to the driving elements being retained in the respective initial position when the spindle is at a standstill. In this case, the radial force on the driving elements, which is caused by the thrust piece and, if appropriate, by the compression spring used, is overcome, so that it becomes easier for the bobbin tubes to be attached or detached on the respective spindle shank.
For the nonpositive fastening of the individual tube coupling on the spindle shank, threaded bores are arranged on the basic body. In order to avoid unbalances, at least two opposite bores with corresponding locking screws are used preferably for each tube coupling.
It is normally sufficient if one clamping piece and at least one of the proposed tube couplings are arranged for the defined fixing of the bobbin tube on the respective spindle shank.
If relatively long bobbin tubes are used or if bobbin tubes which could experience pronounced deformation as a result of high thread tensions are employed, two or more tube couplings may also be arranged for the nonpositive and centric fixing of the respective bobbin tube on the spindle shank.
The advantages of the proposed technical solution are, in summary, that a tube coupling is now available by means of which the defects of the known prior art are reliably overcome. As a result of it being formed from individual elements which can easily be produced, the tube coupling can be manufactured efficiently. It ensures, in particular, that the respective spindle shank can be equipped and stripped without obstruction, this being conducive to the use of appropriate mechanisms on the respective textile machine. Due to the variable use of the tube coupling, the latter can be employed not only for the widest possible variety of materials of the bobbin tube used, but also for the widest possible diversity of geometries of the bobbin tubes and for any desired thread tensions. A decisive advantage, at the same time, is that the play between the inside diameter of the bobbin tube and the outside diameter of the tube coupling may, in practice, be selected within a wide range, without eccentricities and consequently, in particular, unbalances exerting mechanical load having to be taken into account at the same time during the running of the spindle.
According to an aspect of the present invention, a play-free and centering tube coupling for nonpositively connecting a tube receptacle to a spindle shank of a textile machine includes a body, a thrust piece arranged axially moveably within the body, and an end piece fixedly connected to the body. The thrust piece has at least one face and the end piece has at least one face. At least three driving elements are arranged centrically and adapted to bear against an inner wall of the tube receptacle. The driving elements are arranged so as to be movable predominantly radially between the body and the thrust piece. Guide slope in the form of a conical collar arranged on the thrust piece is arranged to contact the at least three driving elements, and detaining centrifugal elements are positioned between the thrust piece and the end piece and are displaceable predominantly in a radial direction. At least one of the at least one faces of the thrust piece and of the end piece is arranged as an additional guide slope positioned to contact the detaining centrifugal elements.
According to another aspect of the present invention, there is a difference in dimension between an outer radius of the body and an outer radius of a middle cylindrical part of the thrust piece has at least a size of a diameter of a spherical driving element.
Additionally, other aspects of the present invention are provided including driving element further having a cap-shaped part attached to the body, and a difference in dimension between an outer radius of the body and an outer radius of a middle cylindrical part of the thrust piece has at least the size of an overall dimension of a spherical part of the driving element including an attached cap-shaped part of the driving element.
In another aspect of the present invention, the at least three driving elements are one of spherical elements and caps with inner balls. According to a further aspect of the present invention the caps are equipped with a stop collar. In another aspect of the present invention the body contains receiving receptacles arranged in a radial configuration to receive the at least three driving elements.
According to a further aspect of the present invention, the receiving receptacles comprise one of cylindrical bores as a prismatic perforation and cylindrical bores with an outer spherical narrowing. According to a still further aspect of the present invention, each at least one face of the thrust piece and each at least one face of the end piece are positioned to form additional guide slopes arranged to retain the centrifugal detaining elements, and wherein the guide slope and the additional guide slopes have selectable inclinations relative to a horizontal plane.
According to a further aspect of the present invention, the guide slope for the at least three driving elements on the thrust piece has a selectable angle. In another aspect of the present invention, the guide slope of the thrust piece has an angle of 40xc2x0 relative to the horizontal plane. According to a still further aspect of the present invention the at least one face of the end piece is arranged as an additional guide slope, and the guide slope of the thrust piece and the additional guide slope each have a selectable angle.
Further aspects of the invention include the guide slope of the thrust piece and the additional guide slope each having an angle of 10xc2x0 relative to a horizontal plane. According to other aspects of the present invention the detaining centrifugal elements are one of (1) spherical rollers and (2) cylindrical rollers positionable to fix the thrust piece in a working position.
Further aspects of the invention include at least three radially arranged guide tracks formed between said thrust piece and said end piece for said detaining centrifugal elements arranged between said end piece and said thrust piece. According to another aspect of the present invention the thrust piece is equipped with a sliding bush positioned to ensure axial displaceability of said thrust piece on the spindle shank.
According to a further aspect of the present invention, the body further comprises an assembly collar for fixing the end piece in the body. According to a still further aspect of the invention, a positive connection to be made after conclusion of assembly of the tube coupling is produced between the body and the end piece.
According to an aspect of the present invention, a compression spring ensuring a lowest possible position of the thrust piece in the body is arranged between the end piece and the thrust piece. According to another aspect of the present invention, an elastic band is arranged on an outer circumference of the body to cover the receiving receptacles, whereby the driving elements are retained in an initial position when the spindle shank is at a standstill.
In another aspect of the present invention, the body further includes threaded bores for nonpositively fixing the tube coupling on the spindle shank. According to a further aspect of the present invention, in combination with a spindle shank, and a tube receptacle, at least one clamping piece and at least one tube coupling is arranged for a nonpositive and centric fixing of the tube receptacle on the spindle shank. According to a further aspect of the present invention, in combination with a spindle shank, and a tube receptacle, at least two tube couplings are arranged for a nonpositive and centric fixing of the tube receptacle on the spindle shank.
In another aspect of the present invention, a play-free and centering tube coupling adapted for nonpositively connecting a tube receptacle to a spindle shank of a textile machine includes a cylindrical body having a first axial bore, a cylindrical thrust piece having a second axial bore, the thrust piece being concentrically located and axially moveable within the body, and a cylindrical end piece having a third axial bore, the end piece being fixedly connected to the body. At least three driving elements being circumferentially arranged and radially spaced within the body so as to bear against an inner wall of the tube receptacle. The at least three driving elements are configured to be movable predominantly in a radial direction between the body and the thrust piece. Guide slope in the form of a conically shaped collar is arranged on the thrust piece and is in contact with the at least three driving elements. Detaining centrifugal elements displaceable predominantly in a radial direction arranged between the thrust piece and the end piece.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.